Many airplanes and recreational vehicles (“RVs”) have adjustable seats that can move in several directions. For example, some seats permit a user to move the seat forward and backward, side-to-side, and around a central axis (e.g., rotational motion). For each of these three types of movement, many different systems have been used to control seat positioning.
One system for controlling rotational movement includes using a disc or ring attached to a base assembly, which is attached to the floor of an airplane. The disc or ring includes gear-like teeth disposed along the outer circumference of the disc or ring. A mating gear-like locking mechanism is attached to the seat, which can rotate freely when the user disengages the locking mechanism from the disc or ring. When the user wishes to prevent further rotational movement of the seat, the user engages the locking mechanism, which permits a gear-like tooth to sit between one of the teeth disposed on the disc or ring.
However, the “gear” design has some drawbacks. For example, there are only a finite number of positions in which a user can securely position the seat. Depending on the width of the gear teeth, the angular distance between positions can be significant.
In addition, the seat can get stuck “between” teeth (e.g., locking mechanism not properly engaged between gear teeth). This can cause an undesirable situation in which the user incorrectly believes that the seat is locked. For example, in an airplane, a user holding a hot cup of coffee can be burned if a seat that is improperly “locked” jolts into a proper locked position when the airplane turns at a sharp angle or suddenly experiences turbulence.